The goal of this T32 Training Program proposal is to facilitate the development of a new generation of medical and surgical fetal specialists that will be well trained to carry out innovative and scientifically rigorous laboratory and clinical research directed toward novel and effective strategies for fetal treatment. The need for such a program is highlighted by the present lack of specific subspecialty training and preparation of investigators for treatment of the fetus as a patient. At the same time, the perception of the fetus as a patient is gaining momentum, and the number of claimed successful interventions applicable to the fetus has increased rapidly. There is thus a compelling need for well trained physician scientists in this field for developmental research and analysis of efficacy and outcomes. The Program will support Trainees for up to 3 years of clinical or laboratory research training at the postdoctoral fellowship level. The Training faculty includes 16 Faculty Mentors from The Children's Hospital and the University of Pennsylvania School of Medicine and 1 from Cornell University, who have outstanding credentials and a focused interest in laboratory or clinical research directed toward fetal treatment. These mentors will supervise Trainees in basic laboratory research and/or patient-oriented research projects related to fetal treatment. Research opportunities will include four major areas of basic research 1) Stem cell therapy in the fetus; 2) Fetal gene therapy; 3) Fetal wound healing; and 4) Fetal anatomic malformations and fetal lung growth. Patient oriented research opportunities will be derived from the CHOP Center for Fetal Diagnosis and Treatment and will include opportunities derived from two existing NICHD sponsored multicenter, randomized, clinical trials examining fetal treatment of myelomeningocele and Twin-Twin Transfusion Syndrome at CHOP as well as participation in the design and implementation of new studies of various aspects of fetal therapy. The Program includes training in all aspects of research, including biostatistics and bioethics, with a specific program in ethics in the context of fetal therapy, molecular biology, and related. The Program is strongly supported by access to a superb range of institutional resources, including the CHOP Center for Fetal Diagnosis and Therapy, the CHOP GCRC and the U. Penn Graduate School and IHGT. This request is made for 2 Trainee slots in year 1, 3 Trainee slots in year 2, and 4 Trainee slots each year thereafter.